THE  UNIVERSITY 

OF  ILLINOIS 

LIBRARY 

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A6RICULTURAL 
UIBW 


UNIVERSITY  OF  ILLINOIS 

Agricultural  Experiment  Station 


BULLETIN  No.  232 


I:  POTASH  SHALES  OF  ILLINOIS 

II:  GEOLOGY,  DISTRIBUTION,  AND  OCCUR- 
RENCE IN  UNION  COUNTY 

III:  FINELY-GROUND  SHALE  AS  A  SOURCE  OF 
POTASSIUM  FOR  SOIL  IMPROVEMENT 


A  joint  publication  by  the  Division  of 
Applied  Chemistry  of  the  University  of  Illi- 
nois; the  Illinois  Geological  Survey;  and 
the  Agricultural  Experiment  Station 


URBANA,  ILLINOIS,  MARCH,  1921 


CONTENTS  OF  BULLETIN  No.  232 

PART  I:    POTASH  SHALES  OF  ILLINOIS  PAGE 

Introduction 229 

Constitution  of  Illinois  Potash  Shales 231 

Extraction  and  Concentration  of  the  Potash 235 

Conclusions .   235 

PART  II:    GEOLOGY,  DISTRIBUTION,  AND  OCCURRENCE   OF  THE 
POTASH-BEARING  SHALE  OF  UNION  COUNTY 

Introduction 237 

Topography 237 

Character  of  the  Shale  and  Associated  Rocks 238 

Availability 241 

Localities  of  Possible  Commercial  Importance 241 

Localities  Mainly  of  Local  Importance 243 

PART  III:    FINELY-GROUND  SHALE  AS  A  SOURCE  OF  POTASSIUM 

FOR  SOIL  IMPROVEMENT  .  .  244 


FOREWORD 

Some  five  years  ago  Professor  S.  W.  Parr,  of  the  Division  of 
Applied  Chemistry  at  the  University  of  Illinois,  began  a  'somewhat 
exhaustive  study  of  Illinois  shales  as  a  source  of  oil,  samples  being 
furnished  by  the  State  Geological  Survey,  and  as  in  all  such  cases 
gave  careful  attention  to  possible  by-products.  Most  of  the  shales 
examined  proved  poor  in  oil-bearing  properties,  but  some  of  them  were 
surprisingly  rich  in  potassium  compounds. 

Dr.  Robert  Stewart,  of  the  Agronomy  Department,  in  common  with 
other  students  of  soil  fertility,  was  at  the  same  time  interested  in  every 
possible  source  of  potassium  available  for  agricultural  purposes.  Upon 
being  advised  by  Professor  Parr  of  the  promising  character  of  Illinois 
shales,  he  began  at  once  experiments  intended  to  show  whether  the  par- 
ticular potassium  compounds  present  in  these  shales  could  be  made 
available  for  agricultural  purposes. 

The  present  publication  consists  of  three  parts :  Part  I,  prepared 
by  Professor  Parr  and  Mr.  Austin,  of  the  Division  of  Applied  Chem- 
istry, presents  a  brief  account  of  the  potassium-bearing  quality  of 
these  shales;  Part  II,  prepared  by  Mr.  Frank  Krey,  of  the  State 
Geological  Survey,  gives  the  location  and  approximate  extent  of  the 
deposits;  and  Part  III,  prepared  by  Dr.  Stewart,  reports  the  pre- 
liminary investigations  into  the  agricultural  side  of  the  problem. 

While  further  experimentation  will  be  necessary  to  determine 
whether  these  potassium  compounds  can  be  made  available  under  field 
conditions,  enough  has  been  done,  not  only  to  show  the  presence  of 
vast  amounts  of  this  valuable  material  in  Illinois  shales,  but  also  to 
demonstrate  that  the  compounds  are  capable  of  reduction  by  agri- 
cultural plants  grown  under  laboratory  conditions. 

E.  DAVENPORT 


FIG.  1. — EFFECT  OF  SHALE  ON  THE  PRODUCTION  OF  CORN 

The  pots  were  filled  with  peaty  soil  to  which  was  added  the  materials  indicated. 
The  yield  of  corn  fodder  on  the  shale  pots  was  twice  that  on  the  check  pots.  See 
page  251  for  further  particulars  concerning  this  experiment. 


PART  I 

POTASH  SHALES  OF  ILLINOIS 

BY  S.  W.  PARE,  PROFESSOR  OP  APPLIED  CHEMISTRY,  AND 
M.  M.  AUSTIN,  ASSISTANT  IN  CHEMISTRY 

During  the  years  1916  and  1917  certain  Illinois  shales  were  being 
studied  in  the  laboratory  of  applied  chemistry  at  the  University  of 
Illinois,  with  primary  reference  to  the  amount  of  oil  they  would 
produce  upon  destructive  distillation. 

The  shale  from  only  one  region,  Johnson  county,  proved  to  be 
sufficiently  rich  in  oil  (45  to  50  gallons  per  ton  of  shale)  to  be  of 
interest  for  its  oil  yield  alone.  Numerous  other  shales  were  found 
giving  from  15  to  20  gallons  per  ton,  and  hence  of  questionable  value 
from  a  consideration  of  their  oil  possibilities  alone.  This  constituted, 
therefore,  a  primary  reason  for  examining  all  samples  for  other  values, 
such  as  phosphorus  and  potash.  The  samples  were  furnished  thru  the 
courtesy  of  the  Illinois  State  Geological  Survey  and  came  mainly  from 
the  southern  part  of  the  state.  Phosphorus,  except  in  insignificant 
amounts,  was  not  found  in  any  of  the  shales.  Certain  samples,  how- 
ever, gave  a  percentage  of  potash  quite  unexpected  and  quite  unusual 
for  material  of  this  type. 

It  is  fairly  well  conceded  by  students  of  the  potash  situation  in 
this  country,  at  least  from  the  chemical  viewpoint,  that  the  most  hope- 
ful source  for  a  domestic  supply  resides  chiefly  as  a  by-product  from 
the  manufacture  of  cement.  The  shale  or  other  siliceous  material  that 
enters  into  the  raw  mix  for  cement-making  always  carries  a  certain 
percentage  of  potash.  In  the  process  of  burning  the  clinker,  this 
potash  assumes  the  volatile  form ;  hence  it  may  be  recovered  by  simple 
methods  of  condensation  and  leaching.  Even  tho  the  average  shale  as 
used  in  the  cement  mix  does  not  contain,  on  the  average,  more  than 
from  1.5  to  2.5  percent  of  potash  (K20),  still  the  potential  supply 
from  this  source,  in  the  aggregate,  would  be  very  great. 

The  Illinois  shales  that  we  are  here  considering,  instead  of  having 
an  average  potash  content  of  2  or  even  21/2  percent,  have  a  content  of 
5  percent,  in  the  raw  state.  They  compare,  therefore,  very  favorably 
with  the  green  sands  of  New  Jersey,  concerning  which  not  a  little 
consideration  is  now  being  given  both  in  the  literature  and  financially, 
as  a  possible  source  of  supply  for  this  important  product.1  The  first 

1Chem.  and  Met.  Eng.,  22,  815.     1920. 

229 


230 


BULLETIN  No.  232 


[March, 


question  that  naturally  arises,  therefore,  relates  to  the  suitability  of" 
these  Illinois  shales  with  reference  to  their  main  constituents  for  the 
purpose  of  compounding  into  a  suitable  cement  -mix.  The  best 
authority  on  this  phase  of  the  topic  is  Professor  A.  V.  Bleininger,  who 
in  his  study  of  Illinois  shales  for  cement-making,1  gives  analyses  for 
eight  samples  which  he  deems  suitable  for  such  a  purpose. 

They  show  so  little  variation  in  composition  that  for  purposes  of 
illustration  in  this  discussion  they  may  be  fairly  represented  by  an 
average  value  for  each  constituent.  These  values  are  given  in  the 
second  column  of  Table  1.  For  comparison,  therefore,  as  to  their 
suitability  along  cement  lines,  two  of  the  high-potash  shales  are  shown 
in  parallel  columns  3  and  4. 

TABLE  1. — COMPARISON  OF  ILLINOIS  SHALE  CONSTITUENTS  WITH  REFERENCE 
TO  THEIR  CEMENT-MAKING  PROPERTIES 


Average  of  eight 
Illinois  shales 
(Bleininger) 

Sample  No.   1 
Illinois  potash 
shales 

Sample  No.  2 
Illinois  potash 
shales 

SiO,  . 

61  56 

53.8 

55.0 

Al.O,  . 

16  12 

17  7 

163 

Fe,O,  . 

296 

581 

601 

Fe  O  

3  52 

CaO    

094 

0  7 

0.3 

MgO  .. 

1  79 

1.8 

1.5 

K2O    

2.90 

5.0 

4.9 

Na2O    

0.82 

0.5 

0.4 

Ignition  loss  

6.72 

11.9 

13.0 

1Total  iron  calculated  to  Fe2O,. 

Probably  the  most  characteristic  feature  of  this  table  from  the 
cement-making  standpoint  is  the  ratio  between  the  silica  (Si02)  and 
the  alumina  (A1203).  According  to  the  average  American  practice, 
this  ratio  should  fall  between  2.5  and  3.5.  Upon  calculating  these 
ratios  for  shale  samples  Nos.  1  and  2  of  the  table,  we  have : 


Shale  No.  1 
Shale  No.  2 


53.8 
17.7 
55.0 


=  3.02 
=  3.37 


Hence,  it  is  evident  that  on  the  basis  of  the  silica-alumina  ratio 
the  two  samples  of  the  potash  shales  under  consideration  are  seen  to 
be  in  the  most  advantageous  zone. 

Since,  in  the  process  of  compounding  to  produce  a  suitable  cement 
clinker,  a  shale  is  mixed  with  from  two  to  three  times  its  weight  of 
limestone,  it  follows  that  the  percentage  of  K20  in  the  raw  mix  is 
correspondingly  reduced.  In  the  average  American  practice  this  fac- 
tor amounts  to  from  0.7  to  1.0  percent,  and  on  this  basis  with  a  66% 

'111.  State  Geol.  Survey  Bui.  17,  p.  101.     1912. 


19i!l]  PART  I:   POTASH  SHALES  OF  ILLINOIS  231 

percent  recovery  of  the  total  potash  there  would  result  an  average 
yield  of  about  2.9  pounds  of  K20  per  barrel  of  cement  made.  On  the 
same  basis  the  potash  shales  as  given  in  columns  3  and  4  of  Table  1 
should  show  a  yield  of  5.4  pounds  per  barrel. 

On  this  basis,  estimating  the  price  of  potash  at  15  cents  per  pound, 
the  shales  here  studied  would  return  a  value  for  the  potash  recovery 
alone  of  82  cents  per  barrel  of  cement  made,  as  against  19%  cents 
recovery  from  the  average  potash  content  of  the  ordinary  raw 
cement  mix. 

Reference  thus  far  has  been  made  only  to  the  shale  values  from 
Union  county  in  southern  Illinois.  But  one  other  region  in  the  state 
has  thus  far  supplied  a  shale  with  a  high  potash  content.  This  has 
come  from  the  neighborhood  of  Dixon,  in  Lee  county.  This  shale 
shows  a  potash  content  in  the  raw  state  of  5.8  percent.  It  is  coarse- 
grained, friable,  and  while  of  a  green  color  suggestive  of  the  eastern 
green  sand,  the  geological  character  of  the  material  is  quite  different. 

CONSTITUTION  OF  ILLINOIS  POTASH  SHALES 

The  shales  from  Union  county  are  peculiar  in  that  they  have  a 
small  percentage  of  oil  which  is  present  in  the  free  state.  This  has  no 
industrial  significance,  but  being  volatile  it  adds  to  the  other  volatile 
constituents,  such  as  water  of  hydration,  so  that  upon  ignition  the 
reduction  in  weight,  as  shown  in  Table  1,  amounts  "to  about  12y2 
percent  of  the  raw  material ;  hence  upon  ignition  the  potash  content 
of  the  residue  is  seen  to  be  5.75  percent.  With  the  Dixon  shale  but 
little  loss  on  ignition  occurs  (see  Table  3)  ;  hence  the  potash  percentage 
remains  about  the  same  in  either  the  ignited  or  the  raw  state. 

For  determining  the  form  of  combination  in  which  the  potash  is 
held,  no  very  simple  or  direct  method  is  available.  One  procedure  con- 
sists in  digesting  one  gram  of  the  sample  with  25  cc.  of  concentrated 
sulfuric  acid,  heating  the  same  until  about  half  of  the  acid  has  been 
removed,  diluting,  filtering,  washing,  and  igniting  the  residue,  and 
analyzing  it  for  total  potash.  The  percentage  of  potash  lost  is  con- 
sidered as  being  in  some  other  than  the  feldspathic  form. 

By  this  procedure  62  percent  of  the  total  potash  was  found  to  be 
removed  from  the  Union  county  shales,  while  from  the  Dixon  shale 
only  about  15  percent  was  removed.  This  shows  a  marked  difference 
in  the  chemical  composition  of  the  two  shales.  Further  proof  of  this 
difference  was  desired.  It  is  true  that  in  the  process  of  cement  manu- 
facture the  potash  would  be  equally  recoverable  in  either  case ;  never- 
theless, from  any  other  standpoint,  differences  in  the  ease  with  which 
the  potash  might  be  removed  by  chemical  solvents  or  concentrated  into 
a  form  for  more  ready  extraction,  might  make  a  wide  difference  in  the 
value  of  the'  shales  from  the  two  sources. 

It  is  not  the  purpose  of  this  discussion  to  go  into  the  details  of  the 
experiments  to  determine  the  chemical  character  of  the  potash-bearing 


232  BULLETIN  No.  232  [March, 

constituents.  The  method  of  analysis  just  described  suggests  that  the 
potash  in  the  Dixon  shale  is  chiefly  or  altogether  feldspathic  in  com- 
bination, and  that  the  major  part,  at  least  of  the  potash  in  the  Union 
county  shale,  is  in  some  combination  more  nearly  resembling  the 
glauconitic  or  green-sand  formations.  These  formations  are  considered 
as  being  potassium  iron  silicates  with  an  average  potash  content  vary- 
ing from  5  to  7  percent  K20. 

With  the  marked  difference  in  type  suggested  by  the  analytical 
results  obtained  from  the  use  of  concentrated  sulfuric  acid,  it  seemed 
worth  while  to  prepare  thin  sections  for  study  under  the  microscope. 
No  very  positive  information  came  from  such  studies.  In  general  it 
seemed  evident  that  the  Union  county  shales  had  passed  thru  extensive 
secondary  decompositions  and  that  the  Dixon  shales  had  not.  Both 
types  however,  even  in  the  undisturbed  condition  of  the  deposits,  had 
their  ultimate  particles  in  such  a  finely  divided  state  as  to  render 
impossible  their  resolution  and  study  under  the  microscope. 

A  third  method  of  study  into  the  probable  type  of  composition 
suggested  itself  as  follows: 

Accepting  the  generally  conceded  fact  that  potash  in  feldspathic 
combination  is  but  very  little,  if  at  all,  directly  available  as  plant  food, 
it  might  afford  further  data  on  composition  if  experiments  were 
inaugurated  to  determine  whether  the  Union  county  shales  contained 
some  of  their  potash  in  a  form  which  was  directly  available  for  plant 
use.  Some  foundation  for  this  theory  was  already  afforded  by  the 
fact  that  62  percent  of  the  total  potash  in  those  shales,  as  already 
determined  by  analysis,  was  soluble  in  acid;  thus  furnishing  a  start- 
ing point  in  the  evidence  as  to  their  difference  from  feldspathic 
material.  Moreover,  if  the  Union  county  shales  responded  to  plant 
requirements  and  the  Dixon  shales  did  not,  the  evidence  would  pro- 
ceed one  step  further.  And  again,  if  the  Union  county  shales  were 
treated  with  strong  acid  in  such  a  manner  as  to  remove  all  their  acid- 
soluble  potash,  and  if,  after  being  freed  from  acid,  the  residue  with  the 
remaining  38  percent  of  potash  (presumably  in  feldspathic  combina- 
tion) was  submitted  to  plant  action  and  was  found  lacking  in  avail- 
able potash,  this  would  afford  a  still  further  proof  in  the  chain  of  evi- 
dence as  to  the  type  of  potash  combination  in  the  original  shale. 

Fortunately  at  this  stage  of  the  chemical  studies,  upon  appealing 
to  the  Agronomy  Department  of  the  College  of  Agriculture  for  help 
in  conducting  the  necessary  pot  cultures,  it  was  found  that  such  a 
procedure  fitted  in  well  with  a  program  of  their  own  concerning 
studies  on  the  availability  of  potash  as  plant  food,  in  a  series  of  natural 
substances;  hence  the  potash  shales  in  hand  would  furnish  an  addi- 
tional type  of  material. 

It  is  not  the  purpose  in  this  part  of  the  discussion  to  go  into  the 
details  of  the  results  from  these  pot  cultures  further  than  to  correlate 


1921] 


PART  I:   POTASH  SHALES  OF  ILLINOIS 


233 


the  results  in  so  far  as  they  have  a  bearing  upon  the  shale  composition 
as  already  set  forth. 

In  Table  2,  therefore,  an  attempt  is  made  to  show  the  behavior  of 
the  various  shale  materials  applied  to  a  peat  soil  deficient  in  potash. 
Buckwheat  was  selected  as  the  plant  most  responsive  to  the  varying 
treatments.  An  equivalent  quantity  of  potash  was  added  in  each 
case,  except  of  course,  to  the  check  pot,  which  being  used  for  compari- 
son was  without  addition  of  potash  in  any  form.  Each  pot  was  made 
up  of  7  kilos  of  peat  soil,  60  grams  of  pulverized  limestone,  and  the 
various  types  of  shale  material  ground  to  pass  a  100-mesh  sieve  and 
in  an  amount  that  would  carry  into  the  soil  mixture  in  each  case  a 
total  potash  content  of  1.34  grams. 

TABLE  No.  2. — COMPARATIVE  STUDY  OF  PLANT  GROWTH   (BUCKWHEAT)   USING 
SHALE  MATERIALS  OF  DIFFERENT  COMPOSITION 


DESCRIPTION  OF  POTS 

CONDITION  OF  PLANTS  Six  WEEKS 
AFTER  PLANTING 

No.  1 
Check  pot  using  peat  soil  with  in- 
sufficient potash 

Poor  growth 

No.  2 
Peat  soil  as  in  No.  1,  with  Dixon 
shale 

Poor  growth,  not  distinguished  from 
No.  1 

No.  3 
Peat  soil  as  in  No.  1,  with  Union 
county   shale,   less    62    percent   of 
potash  by  acid  extraction 

Poor  growth,  not  different  from  Nos. 
1  and  2 

No.  4 
Peat  soil  as  in  No.  1,  with  Union 
county  shale  ignited 

Excellent  growth  more  dense  and  taller 
than  Nos.  1,  2,  or  3 

No.  5 
Peat  soil  as  in  No.  1,  with  Union 
county    shale,    sample    No.    1    not 
ignited 

Excellent  growth,  not  distinguishable 
in  density  or  vigor  from  No.  4 

No.  6 
Peat  soil  as  in  No.  1,  with  Union 
county    shale,    sample    No.    2    not 
ignited 

Excellent  growth,  equal  in  every  re- 
spect to  Nos.  4  and  5 

This  amount  of  potash  represents  the  weight  per  acre  that  would 
be  present  in  a  normal  soil  which  was  deemed  to  have  an  adequate 
supply  of  that  constituent.  The  results  as  presented  in  the  table  are 
also  very  clearly  shown  in  the  photographic  reproduction. 

Pot  No.  1  is  the  check,  with  deficient  potash.  No.  2  has 
the  standard  equivalent  of  1.34  grams  of  K20  added  in  the  form 
present  in  the  Dixon  shale,  and  No.  3  has  the  same  addition  in  the 
form  of  acid-insoluble  residue  from  the  Union  county  shale.  An  exam- 


234 


BULLETIN  No.  232 


[March, 


ination  of  these  three  pots  seems  to  warrant  the  conclusion  that  potash 
in  any  available  form  is  lacking  in  each  case.  This,  therefore,  would 
seem  to  confirm  the  previous  assumption  that  the  potash  present  in 
Pots  2  and  3  is  in  the  f eldspathic  form. 


FIG.  2. — BUCKWHEAT  PLANTS  GROWING  ON  PEAT  SOIL  TO  WHICH  VARIOUS 
SHALE  MATERIALS  HAVE  BEEN  ADDED 


1 
Check 


2 

Dixon 
Shale 


Union  Co. 
Acid  ex- 
tracted 


Union  Co. 
Ignited 


Union  Co. 

No.  1.    Not 

ignited 


6 

Union  Co. 

No.  2.    Not 

ignited 


By  further  reference  to  Pots  4,  5,  and  6,  there  is  an  equally  obvious 
indication  that  in  these  pots  there  is  potash  present  in  a  form  available 
for  plant  use;  and  since  the  only  variable  in  the  experiment  is  the 
acid-soluble  constituent,  it  is  evident  that  the  potash  utilized  by  the 
plant  comes  from  this  source. 

Moreover,  ignition  or  non-ignition  of  the  shale  does  not  affect  the 
property  of  the  potash  so  far  as  food  availability  is  concerned.  It 
would  be  of  scientific  interest,  of  course,  to  be  able  to  say  more 
definitely  what  was  the  form  of  potash  combination  here  found.  We 
have  compared  it  thus  far  in  the  discussion  to  the  green  sands  of  the 
eastern  United  States,  which  are  true  glauconites.  The  most  that  can 
be  said  of  these  shales  is  that  they  are  glauconitic  in  type.  They  may 
have  been  originally  a  feldspathic  deposition  which  has  undergone 
secondary  decomposition  in  situ.  Indeed,  the  region  has  other  striking 
examples  of  secondary  decomposition  products  resulting  from  similar 
methods  of  decomposition;  for  example,  the  very  pure  deposits  of 


3921]  PART  I:    POTASH  SHALES  OF  ILLINOIS  235 

amorphous  silica,  found  so  abundantly  in  Union  county.  So  far  as 
conformity  to  green-sand  or  glauconitic  conditions  is  concerned,  there 
is  every  justification  for  such  a  classification,  as  may  be  seen  from  the 
following  quotation,1  indicating  the  geological  conditions  under  which 
the  true  glauconites  are  supposed  to  have  been  formed : 

' '  The  organic  matter  transforms  the  iron  into  sulfid  which  may  be  oxidized 
to  hydrate,  sulfur  being  at  the  same  time  liberated.  This  sulfur  would  oxidize 
to  sulf uric  acid,  which  would  decompose  clay,  setting  free  colloidal  silica,  aluminum 
being  removed  in  solution.  Thus,  we  have  colloidal  silica  and  hydrated  iron  in 
a  state  most  suitable  for  their  combination.  The  potash  which  is  necessary  to 
complete  the  composition  of  glauconite  may  be  derived  from  the  decomposed 
fragments  of  crystaline  rocks  like  orthoclase  or  white  mica." 

Upon  analysis  of  the  shale  for  iron  in  the  pyritic  form  by  methods 
developed  in  this  laboratory,2  it  appears  that  when  the  pyritic  iron 
is  deducted  from  the  total  iron  of  the  shale  there  remains  3.8  percent 
of  iron  available  for  combination  with  the  3.1  percent  of  potash  pres- 
ent in  the  acid-soluble  form,  an  amount  which  approaches  the  ratio  for 
glauconitic  material  with  sufficient  approximation  to  warrant  the 
classification  thus  proposed ;  viz.,  not  true  glauconite  but  glauconitic 
in  type. 


EXTRACTION  AND  CONCENTRATION  OF  THE  POTASH 

It  is  perhaps  sufficiently  evident  from  the  preceding  description 
of  the  composition  of  all  these  shales  that  no  practical  method  for  the 
extraction  of  the  potash  on  an  industrial  basis  is  possible.  This  con- 
dition, however,  does  not  preclude  the  method  of  extraction  by  way 
of  the  cement-making  process.  In  any  case  where  the  by-products 
have  values,  such  a  combination  process  may  come  within  the  range 
of  industrial  possibility.  It  is  not  considered  essential  to  this  dis- 
cussion to  give  the  details  of  the  experiments  directed  toward  extrac- 
tion or  solution  methods  for  direct  recovery  of  the  potash.  While 
practicable  as  a  laboratory  procedure,  they  would  not  be  profitable  as 
industrial  processes. 

CONCLUSIONS 

1.  Shales  occur  in  at  least  two  localities  in  Illinois,  which  contain  5  percent 
or  more  of  potash. 

2.  Shale  outcropping  in   several  places  near  Jonesboro,  in  Union  county, 
which  contains  5  percent  of  potash  would  be  suitable,  so  far  as  can  be  determined 
from  its  chemical  composition  and  physical  character,  for  use  in  the  manufacture 
of  Portland  cement. 


'Clarke,  W.  B.,  Jour,  of  Geol.,  13,  p.  509.     1900. 

^Powell,  A.  B.,  with  Parr,  S.  W.,  Univ.  111.  Eng.  Exp.  Sta.  Bui.  No.  111.     1919 


236 


BULLETIN  No.  232 


[March, 


3.  By  using  this  material  in  the  manufacture  of  cement  and  by  applying 
the  known  methods  of  potash  recovery,  a  yield  of  5.3  pounds  of  potash,  repre- 
senting a  value  of  70  to  80  cents  per  barrel  of  cement,  could  be  obtained. 

4.  The  constitution  of  the  southern  Illinois  shale  is  complex.     The  shale 
contains  free  oil,  bituminous  matter,  pyrite,  undecomposed  potassium-bearing  rock, 
feldspathic  in  character,  and  potassium-bearing  material  of  the  nature  of  glau- 
conite  or  green  sand. 

5.  Shale  from  Dixon,  Lee  county,  contains  5.8  percent  of  potash,  which  is 
held  for  the  most  part  in  a  more  stable  condition  than  that  in  the  southern 
Illinois  shale. 

6.  Extraction  of  the  potassium  from  shale  of  either  the  southern  Illinois 
or  the  Dixon  type  by  means  of  solid  or  liquid  reagents  would  seem  to  be  im- 
practicable, because  of  the  cost  of  leaching  and  recovering  potash  from  material 
where  it  is  present  in  such  small  amounts. 

7.  The  plant  availability  of  the  potash  in   the   southern   Illinois  shale  is 
probably  characteristic  of  all  the  material  of  this   type  outcropping    in    that 
locality. 

8.  That  part  of  the  potassium  in  the  southern  Illinois  shale  which  is  soluble 
in  sulfuric  acid,  is  shown  to  be  in  a  combination  of  the  glaueonite  type. 

9.  In  southern  Illinois  shale  having  a  potash  content  of  5.0  percent  in  the 
raw  condition  or  5.6  percent  when  ignited,   62  percent  of  the  total  potash  is 
glauconitic  in  character  and  is  available  as  plant  food. 

TABLE  3. — ANALYSIS  OF  ILLINOIS  SHALES* 


Location 

Sample 
No. 

Ash 

Si03 

A12O3 

Fe2O3 

CaO 

MgO 

K20 

Na2O 

Green  shale  above 

black    shale    at  - 

1 

96.9 

2.9 

Caney  creek  .  .  . 

2 

97.7 

3.5 

3 

86.2 

5.2 

4 

88.0 

5.7 

Black  shale  at 
Caney  creek  ....   < 

6 

7 
10 

88.1 
87.1 
87.3 

61.0 
63.3 
61.5 

20.2 
18.7 
18.7 

6.6 
6.9 
6.5 

0.8 
0.4 
0.9 

2.0 
1.7 
1.8 

5.65 
5.58 
5.7 

0.6 
0.5 
0.6 

11 

85.5 

66.0 

17.8 

6.5 

0.2 

1.3 

5.0 

0.7 

12 

86.0 

5.4 

Black  shale  at  State 

Pond  

8 

89.1 

5.5 

Black  Shale  at  Moun- 

tain Glen 

9 

86  1 

5  6 

Green  feldspathic 

shale  at  Dixon.  .  . 

5 

97.3 

5.8 

*The  factors  for  SiO2,  A12O3,  etc.,  are  referred  to  the  shale  ash  as  100  percent. 


1921]  PART  II:    GEOLOGY  OF  POTASH  SHALE  OF  UNION  COUNTY  237 


PART  II 

GEOLOGY,    DISTRIBUTION,    AND    OCCURRENCE    OF    THE 
POTASH-BEARING    SHALE    OF    UNION    COUNTY 

BY  FRANK  KEEY,  STATE  GEOLOGICAL  SURVEY 

The  black  potash-bearing  shale  of  Union  county  comes  to  the  sur- 
face in  a  belt  75  to  200  feet  wide  along  the  west  slope  of  the  ridge  that 
lies  about  one  mile  west  of  Jonesboro,  trends  a  little  west  of  north,  and 
ends  IVk  miles  south  of  Alto  Pass,  at  Clear  creek,  in  the  Southwest  1/4 
of  Section  22,  Township  11  South,  Range  2  West.  At  its  north  end, 
the  shale  is  terminated  by  a  northwest-southeast  fault  which  brings 
rock  of  the  Chester  age  into  contact  with  Devonian  strata.  The 
southernmost  exposure  of  the  shale  is  seen  in  a  narrow  ravine  in  the 
south-central  part  of  Section  23,  about  half  a  mile  north  of  the  Ham- 
burg road.  South  of  the  Hamburg  road  no  black  shale  occurs,  and 
while  both  the  overlying  and  underlying  rocks  may  be  seen  in  numer- 
ous exposures,  either  the  black  shale  was  never  deposited  here  or  else 
it  was  removed  by  erosion  prior  to  the  deposition  of  the  overlying 
green  shale.  The  southern  limit  of  the  black  shale  is  therefore  within 
half  a  mile  north  of  the  Hamburg  road.  The  exact  limit  can  readily  be 
determined  by  exploration. 

TOPOGRAPHY 

The  ridge  on  whose  western  slope  the  black  shale  outcrops,  is  not 
continuous  but  is  interrupted  at  intervals  by  gaps  formed  where  creeks 
have  cut  their  way  thru  the  hills.  Such  gaps  vary  in  width  from 
less  than  a  quarter  of  a  mile  to  more  than  half  a  mile.  The  crest  of 
the  ridge  is  from  150  to  225  feet  above  the  level  of  the  creek  flats, 
and  the  horizon  of  the  black  shale  is  40  to  100  feet  below  the  crest  of 
the  ridge  except  at  the  gaps  where  the  easterly  dip  of  the  rock  brings 
it  to  the  level  of  the  flat,  usually  within  a  distance  of  an  eighth  to  a 
quarter  of  a  mile  east  of  the  crest. 

In  general,  the  eastern  slope  of  the  ridge  is  gentle,  8  feet  in  100 
being  a  fair  average.  The  western  slope  is  more  abrupt,  especially  the 
upper  100  feet.  Here  vertical,  or  nearly  vertical,  faces  for  short  dis- 
tances are  not  uncommon,  and  slopes  of  15  to  20  feet  or  more  in  100 
prevail.  The  lower  slopes,  however,  are  not  very  different  from  those 
on  the  east  flank. 

Numerous  small  lateral  ravines  which  divide  and  redivide  as  they 
approach  the  crest  add  greatly  to  the  rough  and  broken  character  of 
both  the  east  and  the  west  slopes. 


238  BULLETIN  No.  232  [March, 

CHARACTER  OF  THE  SHALE  AND  ASSOCIATED  ROCKS 

As  the  black  shale  disintegrates  rapidly  on  exposure  to  the 
weather,  good  outcrops  are  met  with  in  only  a  few  particularly  favor- 
able localities.  However,  some  of  the  more  resistant  associated  strata 
are  more  frequently  met  with,  and  therefore  their  outcrops  may  serve 
to  determine  the  location  of  the  shale  in  places  where  it  is  not  exposed. 
For  this  reason,  in  part,  a  somewhat  careful  description  of  the  over- 
lying and  underlying  strata  is  made  here. 

Section  of  the  Black  Shale  and  Associated  Strata 

Feet 

1.  Loess,  gravel,  and  iron  conglomerate  (Cretaceous  or  later) 0-40 

2.  Cherty  rock   (base  of  Burlington) 2-30 

3.  Green  shale  (Springville  shale) 30-60 

4.  Black  potash-bearing  shale    (Mountain  Glen  shale) 35-45 

5.  Brown,  fine-grained  siliceous  and  cherty  limestone . . . .  >  Alto  20  -  25 

6.  Brown,  thin-bedded  siliceous   shale )  formation     30± 

The  loess  is  a  fine,  brown  to  chocolate-colored  siliceous  material, 
probably  wind  blown.  The  gravel  consists  of  well-rounded  chert 
pebbles  which  range  in  size  from  a  pea  to  two  inches  in  diameter,  but 
average  less  than  one  inch.  Fragments  of  iron  conglomerate  (chert 
pebbles  cemented  together  by  iron  oxid)  are  often  found  on  the  slopes. 
No  good  exposure  showing  the  relations  and  separate  thicknesses  of  the 
loess,  gravel,  or  conglomerate  was  seen,  but  field  observations  suggest 
that  the  conglomerate  lies  just  above  the  cherty  rock;  that  the  gravel 
overlies  the  conglomerate ;  and  that  the  gravel  is  in  turn  overlain  by 
the  loess.  The  loess,  gravel,  and  iron  conglomerate  together  make  up 
the  gently  rounded  tops  of  the  ridges. 

The  cherty  rock,  thought  to  be  the  base  of  the  Burlington  lime- 
stone, varies  somewhat  at  different  localities.  In  the  northern  part 
of  the  area  it  is  made  up  of  massive  beds,  2  to  8  feet  in  thickness,  which 
on  their  weathered  surfaces  strongly  resemble  a  quartzite  or  well- 
cemented,  fine-grained  sandstone,  but  where  fresh  appear  to  be  re- 
crystallized  chert.  Four-inch  bands  of  true  chert  or  flint  are  often 
found  along  the  bedding  planes.  Farther  south  the  rock  consists  of 
chert  layers  alternating  with  fine-grained  brown  limestone.  It  is  very 
probable  that  the  ridge  owes  its  origin  to  the  resistant  character  of 
this  cherty  rock. 

The  green  shale,  named  Springville  shale  by  Savage,1  varies  in 
character  from  north  to  south.  In  the  northern  portion  of  its  outcrop 
it  is  probably  a  soft,  laminated  clay  shale,  but  no  good  exposures  are 
seen.  '  Toward  the  south,  however,  the  shale  becomes  progressively 
more  siliceous  and  resistant,  so  that  it  forms  bluffs  10  to  30  feet  high. 


JSavage,   T.   E.      The   Devonian    Formations   of   Illinois.     Amer.   Jour.    Sci., 
Fourth  Series,  Vol.  XLIX,  No.  291,  pp.  169-182.     1920. 


1921]          PART  II:    GEOLOGY  OF  POTASH  SHALE  OP  UNION  COUNTY  239 

Where  fresh,  the  shale  is  greenish  gray,  hard,  and  siliceous;  some 
layers  are  harder  than  others  and  approach  a  chert  in  appearance. 
When  weathered,  the  shale  breaks  up  into  irregularly  shaped  chips 
seldom  more  than  3  inches  long  or  less  than  %  inch  thick.  Such  chips 
have  a  mottled  appearance;  green,  gray,  brown,  and  red  being  the 
prevailing  colors.  At  the  base  of  the  green-shale  formation,  over  most 
of  the  area,  is  a  3-foot  bed  of  compact,  impure  limestone,  blue-gray 
where  fresh,  but  weathering  to  gray-brown.  It  is  characterized  by 
an  abundance  of  small  siliceous  geodes,  seldom  more  than  one  inch  in 
diameter. 

The  black  potash-bearing  shale  beneath  the  green  (Springville) 
shale  is  thought  to  represent  the  youngest  of  the  Devonian  formations 
in  this  region,  and  to  be  the  equivalent  of  the  Chattanooga  shale  of 
Tennessee  and  the  New  Albany  shale  of  New  York.  It  has  been 
named  Mountain  Glen  shale  by  Savage.1  When  fresh  the  shale  is  hard, 
black,  thinly  laminated,  and  slaty.  Pyrite  is  common,  especially  near 
the  base.  On  weathered  surfaces  the  shale  splits  readily  into  thin 
sheets  which  are  lighter  in  color  than  the  unweathered  shale  and  are 
often  stained  red  by  iron.  Beca.use  it  disintegrates  readily  under  the 
influence  of  the  weather,  good  exposures  are  to  be  found  only  along 
stream  courses  or  on  steep  slopes  where  talus  from  overlying  rock  is 
constantly  being  removed  as  fast  as  it  is  formed. 

The  fact  that  analyses  of  the  Mountain  Glen  shale  made  on  samples 
taken  at  the  three  widely  separated  localities  indicated  on  the  accom- 
panying map  have  essentially  the  same  potash  content,  suggests  uni- 
formity in  the  composition  of  the  shale  thruout  its  extent.  For 
analyses  see  Table  3  on  page  236. 

Below  the  black  shale  is  a  fine-grained,  hard,  brown,  siliceous  lime- 
stone. Chert  is  abundant  both  as  layers  and  as  nodules,  and  in  some 
localities  may  make  up  more  than  20  percent  of  the  rock's  mass.  The 
limestone  is  massive  in  its  upper  portion,  but  becomes  increasingly 
argillaceous  with  depth,  until  it  passes  into  a  brown  siliceous  shale. 
The  shale  weathers  into  thin-  layers,  %  to  i/4  inch  thick,  which  com- 
monly break  up  into  small  rectangular  blocks  1  to  2  inches  long.  This 
limestone  and  shale  together  make  up  the  Alto  formation.1 

All  the  above-described  rocks  dip  about  15°  in  an  easterly  direction. 
The  amount  of  dip  varies  somewhat  at  different  localities,  but  in  gen- 
eral it  decreases  to  the  south.  Dips  of  20°  and  more  have  been  observed 
to  the  north,  while  in  the  southern  part  less  than  10°  is  the  common 
angle. 

'Op.  cit. 


240 


BULLETIN  No.  232 
R  2W  , 


Eoad  Section  Township  Outcrop  of  Mountain 

Line  Line  Glen  (potash-bearing) 

Shale 

FIG.  3. — MAP  SHOWING  THE  OUTCROP  OF  THE  MOUNTAIN  GLEN  SHALE  AND 

THE  LOCATIONS  OF  THE  SAMPLES 

The  bold-face  italicized  numbers  are  sample  numbers  and  the  arrows  point  to 
the  locations  where  the  samples  were  taken. 


1921]          PART  II:    GEOLOGY  OF  POTASH  SHALE  OP  UNION  COUNTY  241 

AVAILABILITY 

Altho  the  shale  is  available  in  quantity  at  many  places  along  its 
outcrop,  there  are  only  a  few  localities  which  have  ready  access  to 
railroad  transportation,  and  therefore  have  commercial  possibilities. 

The  Mobile  and  Ohio  Railroad  runs  parallel  to  the  outcrop  for 
several  miles,  but  on  the  east  side,  of  the  ridge.  It  is  therefore 
effectively  separated  from  the  shale  by  the  intervening  hills  except  at 
the  gaps.  From  the  standpoint  of  transportation,  then,  the  most  favor- 
able localities  for  exploitation  of  the  shale  are  at  the  gaps,  specifically 
in  the  Northeast  14  of  Section  34 ;  along  the  branch  of  Caney  creek 
in  the  Southwest  1/4  of  Section  11 ;  at  the  State  pond  in  the  south- 
central  part  of  Section  14 ;  and  along  the  north  slope  of  the  ridge  near 
the  north  quarter-corner  of  Section  23. 


LOCALITIES  OF  POSSIBLE  COMMERCIAL  IMPORTANCE 

Along  Branch  of  Clear  Creek 
NE.  y±  Sec.  34,  T.  11  8.,  R.  2  W. 

The  branch  of  Clear  creek  here  has  a  general  east-and-west  direc- 
tion. North  of  the  creek  is  an  extensive  flat,  but  to  the  south  the  bank, 
which  comprizes  the  end  of  the  main  north-and-south  ridge,  rises 
steeply  from  the  stream  to  a  height  of  about  50  feet,  and  then  more 
gently  to  the  top  of  the  ridge.  The  slope  is  broken  by  numerous  small 
north-and-south  ravines  leading  to  the  creek.  The  black  shale  makes 
up  the  lower  part  of  this  slope  for  a  distance  of  about  300  or  400  feet, 
but  the  eastward  dip  causes  its  outcrop  to  rise  westward  until  it 
reaches  a  position  about  150  feet  above  the  creek,  whence  it  turns 
south  and  follows  the  western  slope  of  the  main  ridge. 

The  black  shale  is  overlain  by  about  25  feet  of  soft  green  shale 
which  is  followed  by  8  to  15  feet  of  cherty  rock ;  and  this  in  turn  is 
overlain  by  a  thickness  of  15  to  30  feet  of  iron  conglomerate,  gravel, 
and  loess.  Along  the  outcrop,  a  strip  50  to  150  feet  wide  (depending 
on  the  slope  of  the  surface),  with  an  average  thickness  of  about  25 
to  30  feet  and  a  length  of  more  than  1,000  feet,  aggregating  more  than 
100,000  tons,  is  practically  free  from  overburden,  and  could  therefore 
be  worked  with  relative  ease.  By  continuing  to  work  along  the  south- 
ward extension  and  by  removing  the  overburden  where  its  thickness  is 
not  prohibitive,  the  tonnage  could  be  more  than  doubled.  The  amount 
of  overburden  that  can  profitably  be  removed  is  dependent  on  the 
value  of  the  shale. 

Transportation  is  afforded  by  the  Mobile  and  Ohio,  which  runs 
about  half  a  mile  east  of  the  outcrop.  The  intervening  ground  is  flat 
and  would  offer  no  obstacle  to  the  building  of  a  spur. 


242  BULLETIN  No.  232  [March, 

Along  Branch  of  Caney  Creek 
SW.  14  Sec.  11,  T.  12  S.,  R.  2  W. 

The  outcrop  along  the  branch  of  Caney  creek  in  Section  11  is  very 
similar  to  that  of  Section  34.  The  creek  here  has  a  northeast-south- 
west direction,  and  the  south  bank  has  a  steep  slope.  The  black  shale 
outcrops  along  the  creek  for  500  to  600  feet  but  rises  to  the  south- 
west, turns  southward,  and  disappears  under  a  cover  of  loess.  Farther 
south  it  reappears  at  places  along  the  western  slope  of  the  main  ridge. 
The  overlying  rocks  are  siliceous  green  shale  about  40  feet  thick,  fol- 
lowed by  a  cherty  limestone  20  feet  and  more  thick,  which  is  capped 
by  loess. 

The  amount  of  shale  available  with  little  or  no  overburden  is  lim- 
ited to  a  narrow  strip  probably  nowhere  more  than  50  or  75  feet  wide, 
and  about  800  feet  long.  The  tonnage  available  under  these  favorable 
circumstances  would  probably  be  less  than  75,000.  The  great  thick- 
ness of  overburden  elsewhere  precludes  its  profitable  removal  except 
perhaps  at  the  southward  bend  of  the  outcrop,  where  the  loess  covering 
might  be  removed  and  additional  tonnage  thereby  be  obtained. 

Transportation  is  afforded  by  the  Mobile  and  Ohio,  which  runs 
about  a  quarter  of  a  mile  east  of  the  outcrop.  The  intervening  ground 
is  flat  and  approximately  at  the  same  elevation  as  the. railroad. 

State  Pond 
South-Central  Part  of  Sec.  '14,  T.  12  8.,  R.  2  W. 

The  State  pond  was  formed  by  damming  a  small  east-and-west 
ravine.  The  south  bank  of  the  pond,  which  is  also  the  north  slope  of  a 
narrow  east-west  ridge,  consists  of  a  bluff  composed  of  green  siliceous 
shale.  Just  below  and  west  of  the  dam  there  is  an  outcrop  of  black 
shale.  The  exposure  is  about  100  feet  long,  but  it  rises  to  the  west  and 
is  lost  under  a  cover  of  loess ;  it  probably  passes  around  the  west  end 
of  the  ridge,  well  up  the  slope,  and  swings  back  east  on  the  south  side 
of  the  ridge  beneath  the  loess.  The  entire  length  of  the  exposure  is 
not  over  300  feet  and  since  it  is  so  steep  as  to  form  a  nearly  vertical 
face,  the  width  of  shale  free  from  overburden  is  less  than  50  feet.  The 
overburden  consists  of  the  green  siliceous  shale  and  loess. 

The  amount  of  shale  that  can  be  obtained  free  from  overburden 
is  small,  probably  less  than  25,000  tons.  However,  should  exploration 
show  the  shale  to  be  present  on  the  south  slope  and  the  loess  over- 
burden to  be  subject  to.  profitable  removal,  a  considerable  additional 
tonnage  could  be  obtained. 

Railroad  transportation  could  be  furnished  by  the  Mobile  and  Ohio 
Railroad,  which  runs  about  an  eighth  of  a  mile  west  of  the  outcrop. 


1921]          PART  II:    GEOLOGY  OF  POTASH  SHALE  OF  UNION  COUNTY  243 

North  Part  of  Sec.  23,  T.  12  8.,  R.  2  W. 

The  black  shale  outcrops  as  a  narrow  band  along  the  east-west  slope, 
south  of  the  Mobile  and  Ohio  tracks  in  the  neighborhood  of  the  north 
quarter-corner  of  Section  23.  About  a  quarter  of  a  mile  west  of  the 
east  line  of  Section  23  the  shale  is  found  at  the  level  of  the  flat,  but  rises 
to  the  west,  and  where  it  turns  south  along  the  west  slope  of  the  ridge, 
is  80  to  100  feet  above  the  flat.  As  the  length  of  the  outcrop  is  not  less 
than  1,200  feet,  the  width  about  100  feet,  and  the  average  thickness 
about  25  feet,  the  available  tonnage  amounts  to  more  than  75,000. 

The  overburden  consists  of  the  green  siliceous  shale,  and  varying 
thicknesses  of  cherty  limestone  and  loess.  The  total  thickness  of  over- 
burden reaches  100  feet  in  places. 

The  Mobile  and  Ohio  Eailroad  runs  along  the  foot  of  the  slope. 

Other  Localities 

About  one  mile  west  of  Mountain  Glen,  at  the  end  of  the  ridge,  in 
Southeast  !/4  of  Section  27,  T.  11  S.,  R.  2  W.,  opposite  the  outcrop  in 
the  Northwest  14  of  Section  34,  the  slope  is  gentle  and  covered  with 
loess.  The  black  shale  undoubtedly  underlies  this  loess,  and  should 
exploration  show  that  it  is  feasible  to  move  the  latter,  large  quantities 
of  shale  might  also  be  obtained  here.  Higher  up  the  ridge,  along  the 
west  slope,  the  black  shale  outcrops  under  conditions  similar  to  those 
at  the  Northwest  14  of  Section  34.  Also  at  the  end  of  the  ridge,  in  the 
Southeast  Vi  of  Section  10  (opposite  the  outcrop  on  the  branch  of 
Caney  creek) ,  and  at  the  end  of  the  ridge  in  the  west-central  part  of 
Section  14  (opposite  State  pond),  similar  conditions  prevail. 

Where  the  black  shale  underlies  the  flats  in  the  gaps,  often  at 
depths  of  less  than  10  feet,  other  possible  localities  for  commercial 
exploitation  are  afforded. 

In  the  event  that  the  value  of  the  black  shale  proves  sufficient  to 
warrant  the  use  of  mining  methods  in  its  recovery,  the  amount  avail- 
able would  be  enormous.  The  shale  probably  underlies  all  the  county 
east  of  its  outcrop  but  becomes  progressively  deeper  to  the  north  and 
east.  However,  at  nearly  any  point  along  the  Mobile  and  Ohio  Rail- 
road, from  one  mile  northwest  of  Jonesboro  to  about  one  mile  south- 
west of  Mountain  Glen,  the  black  shale  can  be  reached  at  depths  rang- 
ing from  30  feet  to  not  more  than  100  feet. 

LOCALITIES  MAINLY  OF  LOCAL  IMPORTANCE 

In  addition  to  the  localities  mentioned  as  possessing  commercial 
possibilities,  the  whole  shale  belt  thruout  its  extent  should  prove  a 
source  for  local  supply.  Its  position  high  up  the  slope  and  the  broken 
character  of  the  topography  make  it  difficult  of  access  even  to  wagons 
at  the  present  time.  However,  roads  can  readily  be  built  at  least  part 
of  the  way,  and  means  can  be  devised  to  get  the  shale  down  to  the  more 
level  country  with  the  aid  of  gravity,  in  those  localities  where  roads 
cannot  be  built  all  the  way  to  the  outcrops. 


244  BULLETIN  No.  232  [March, 

PART  m 

FINELY-GROUND   SHALE   AS   A   SOURCE    OF   POTASSIUM 
FOR  SOIL   IMPROVEMENT 

BY  EGBERT  STEWAET,  CHIEF  IN  SOIL  FERTILITY* 

The  World  War  created  a  potash,  famine  in  America  by  cutting 
off  supplies  from  the  German  potash  deposits.  The  price  of  the  potash 
reserve  in  America  and  the  limited  American  supply  became  so  great 
as  to  prohibit  its  use  in  agriculture.  This  condition,  however,  stimu- 
lated the  search  for  American  sources  of  supply,  with  more  or  less 
success.  Reports  of  these  efforts  have  been  recorded  in  the  various 
scientific  and  technical  journals  of  the  country. 

Early  in  1915  the  Department  of  Agronomy  became  interested  in 
securing  a  cheap  American  source  of  potassium  for  use  on  the  peaty 
lands  of  Illinois,  which,  as  is  well  known,  are  markedly  deficient  in 
potassium  and  respond  generously  to  its  application.  It  seemed  to 
the  writer  that  there  was  no  reason  why  the  so-called  insoluble 
potassium  compounds,  such  as  orthoclase  felspar  and  leucite,  if  finely 
ground,  could  not  serve  as  a  source  of  potassium  for  crop  production 
on  such  soils.  It  is  true  that  finely-ground  materials  such  as  orthoclase 
felspar,  leucite,  and  alunite,  have  been  used  in  such  a  manner  in  the 
past,  but  these  tests,  particularly  in  America,  have  usually  been  made 
on  soil  that  was  not  definitely  known  to  be  deficient  in  potassium,  as  is 
the  peaty  soil  of  Illinois  and  other  sections  of  this  country. 

In  1916,  therefore,  a  series  of  greenhouse  pot  cultures  was  started 
with  peaty  soil  treated  with  finely-ground  leucite,  kainit,  alunite,  and 
ignited  alunite,  in  an  ^ffort  to  determine  the  comparative  value  of 
these  various  forms  of  potassium  for  soil  improvement.  The  peat  was 
dried,  thoroly  mixed,  and  placed  in  four-gallon  earthenware  pots.  The 
potassium  content  of  the  peat,  alunite,  leucite,  and  kainit  was  as  fol- 
lows :  peat,  .3520  percent ;  alunite,  8.91  percent ;  leucite,  9.95  percent ; 
and  kainit,  12.78  percent.  The  outline  of  the  treatment  is  recorded  in 
Table  4. 

Lime  in  the  form  of  finely-ground  limestone  was  applied  at  the 
rate  of  60  grams  per  pot,  or  5  tons  per  acre.  The  amount  of  potassium 
applied  to  each  pot  was  the  same,  1.34  grams  (which  is  equivalent  to 
an  application  of  500  pounds  of  potassium  sulfate  per  acre).  The 
amounts  of  the  different  materials  supplying  the  potassium  were  as. 
follows : 

Alunite 15.05  grams 

Leucite 13.49  grams 

Kainit   10.50  grams 

*Doctor  Stewart  is  now  Dean  of  the  College  of  Agriculture,  University  of 
Nevada. 


1921] 


PART  III:    FINELY  GROUND  SHALE  FOR  SOIL  IMPROVEMENT 


245 


TABLE  4. — POT-CULTURE  EXPERIMENTS  WITH  INSOLUBLE  POTASSIUM  ON 

PEATY  SOILS 

Outline  of  Treatment,  1916 


Pot  No. 

SERIES  I 
WHEAT 

SERIES  II 
OATS 

SERIES  III 
CLOVER 

1 

Lime 

Lime 

Lime 

2 

Lime 

Lime 

Lime 

3 

4 

L,  Kainit 
L,  Kainit 

L,  Kainit 
L,  Kainit 

L,  Kainit 
L,  Kainit 

5 
6 

L,  Alunite 
L,  Alunite 

L,  Alunite 
L,  Alunite 

L,  Alunite 
L,  Alunite 

7 
8 

L,  Leucite 
L,  Leucite 

L,  Leucite 
L,  Leucite 

L,  Leueite 
L,  Leucite 

9 

L,  Leucite 
Magnesium  chlorid 
Sodium  chlorid 

L,  Leucite 
Magnesium  chlorid 
Sodium  chlorid 

L,  Leucite 
Magnesium  chlorid 
Sodium  chlorid 

10 

L,  Leucite 
Magnesium  chlorid 
Sodium  chlorid 

L,  Leueite 
Magnesium  chlorid 
Sodium  chlorid 

L,  Leucite 
Magnesium  chlorid 
Sodium  chlorid 

The  magnesium  chlorid  and  the  sodium  chlorid  were  applied  to 
Pots  9  and  10  at  the  rate  of  3.4  grams  per  pot. 

A  peculiar  condition  at  once  developed.  It  was  impossible  to 
secure  a  normal  growth  of  either  wheat  or  oats  in  any  of  the  pots, 
even  where  kainit  was  added.  The  wheat  and  oat  plants  would  grow 
vigorously  for  five  or  six  weeks,  giving  every  evidence  of  marked  im- 
provement from  the  applications  of  potassium  material.  At  the  end 
of  that  time  they  would  invariably  turn  yellowish  brown  and  no  fur- 
ther growth  would  take  place.  The  condition  persisted  thruout  the 
entire  four  years  of  the  experiment.  As  a  result,  corn  and  buckwheat 
were  substituted  for  wheat  and  oats,  with  very  favorable  results.  The 
yields  obtained  in  1916  are  recorded  in  Table  5. 

The  results  obtained  are  very  suggestive.  Leucite  gave  yields 
which  showed  a  distinct  benefit  from  the  treatment;  the  increases 
were  126  percent  in  the  case  of  the  corn  and  60  percent  in  the  case  of 
the  clover.  Kainit  gave  an  increase  of  326  percent  in  the  yield  of  corn 
and  of  121  percent  in  the  yield  of  clover.  Alunite  gave  some  indica- 
tions of  being  beneficial,  especially  in  the  production  of  corn.  Its 
effect  on  clover,  however,  was  negative.  The  addition  of  sodium 
chlorid  and  magnesium  chlorid  to  the  leucite  in  an  attempt  to  produce 
an  artificial  kainit,  was  no  more  effective  than  the  leucite  itself. 

In  1917  two  additional  pots  for  the  use  of  ignited  alunite  were 
added  to  the  series.  All  pots  received  an  additional  treatment  of 
potash-bearing  material,  as  before.  The  results  are  reported  in  Table  6. 


246 


BULLETIN  No.  232 


[March, 


FIG.  3. — BUCKWHEAT  GROWING  ON  PEATY  SOIL  TO  WHICH  HAS  BEEN  ADDED 
THE  MATERIALS  INDICATED 


FIG.  4. — COMPARATIVE  EFFECT  OF  SHALE  AND  OTHER  MATERIALS  ON  GROWTH 
OF  BUCKWHEAT  ON  PEATY  SOIL 


1921] 


PART  III:    FINELY  GROUND  SHALE  FOR  SOIL  IMPROVEMENT 


47 


TABLE  5. — EFFECT  OF  VARIOUS  FORMS  OF  POTASSIUM  ON  PRODUCTION 
OF  CORN  AND  CLOVER,  1916 

Yields  recorded  as  grams  per  pot,  air- dry  weight 


Pot  No. 

Treatment 

Corn 

Clover 

Individual 

Average 

Individual 

Average 

1 
2 

3 

4 

5 
6 

7 
8 

9 
10 

.Lime  

11 
12 

50 

48 

19 
21 

25 
27 

28 
24 

11.5 

49 
20 
26 

26 

28 
28 

66 
57 

31 
30 

43 

47 

33 

40 

28.0 
62.0 
30.5 
45.0 

5*6.5 

Lime  

L,  kainit  

L,  kainit  

L,  alunite  

L,  alunite  

L,  leucite  

L,  leucite  

L,  leucite,  sodium  chlorid, 
magnesium  chlorid  

L,  leucite,  sodium  chlorid, 
magnesium  chlorid  

TABLE  6. — EFFECT  OF  VARIOUS  FORMS  OF  POTASSIUM  ON  PRODUCTION 
OF  CLOVER  AND  BUCKWHEAT,  1917 

Yields  recorded  as  grams  per  pot,  air-dry  weight 


Pot  No. 

Treatment 

Clover 

Buckwheat 

Individual 

Average 

Individual 

Average 

1 

2 

3 

4 

5 
6 

7 
8 

9 
10 

11 
12 

Lame  

14 
19 

46 
70 

20 
23 

35 
30 

22 
22 

166 
125 

16.5 
58.0 
21.5 
32.5 

22.0 
145.0 

30 

40 

75 

80 

46 
39 

90 
81 

70 
75 

Not  pla: 
buckw 

35.0 
87.5 
42.5 
85.5 

72.5 

ited  to 
heat 

Lime  

L,  kainit  

L,  kainit  

L,  alunite  

L,  alunite  

L,  leucite  

L,  leucite  

L,  leucite,  magnesium  chlorid, 
sodium  chlorid   

L,  leucite,  magnesium  chlorid, 
sodium  chlorid   

Ignited  alunite  

lernited  alunite  . 

Again  the  yields  from  the  use  of  leucite  were  very  favorable. 
Kainit  gave  an  increase  of  251  percent  in  the  yield  of  clover  and  of 
150  percent  in  the  yield  of  buckwheat ;  while  leucite  gave  an  increase 
of  98  percent  in  the  yield  of  clover  and  of  143  percent  in  the  yield 
of  buckwheat.  The  ignited  alunite,  as  was  expected,  gave  remarkable 
increases,  amounting  to  nearly  800  percent. 


248 


BULLETIN  No.  232 


[March, 


FIG.  5. — EFFECT  OF  SHALE  ON  THE  PRODUCTION  OF  RAPE 


FIG.  6. — EFFECT  OF  SHALE  ON  THE  PRODUCTION  OF  SWEET  CLOVER 


1921] 


PART  III:    FINELY  GROUND  SHALE  FOR  SOIL  IMPROVEMENT 


249 


During  1918  various  other  crops  were  tested  out  with  continued 
favorable  indications  for  leucite.    See  Table  7. 

TABLE  7. — EFFECT  OF  VARIOUS  FORMS  OF  POTASSIUM  ON  THE  PRODUCTION 
OF  RAPE  AND  CLOVER,  1918 

Yields  recorded  as  grams  per  pot,  air-dry  weight 


Ka] 

je 

Clove 

r 

Individual 

Average 

Individual 

Average 

1 

1  ji  1I1O       

100 

74 

2 

Lime     

95 

97.5 

75 

74.5 

3 

L    ktiinit  

120 

106 

4 

145 

132.5 

107 

106.5 

5 

L,  alunite  

90 

92 

6 

L,  alunite  •  

90 

90.0 

92 

92.0 

7 

L,  leucite  

116 

99 

8 

L,  leucite  

138 

127.0 

99 

99.0 

9 

L,  leucite,  magnesium  chlorid, 
sodium  chlorid     

112 

106 

10 

L,  leueite,  magnesium  chlorid, 
sodium  chlorid   

110 

111.0 

101 

103.5 

11 

L,  ignited  alunite  

103 

158 

12 

L,  ignited  alunite  

107 

105.0 

147 

152.5 

Kainit  gave  an  increase  of  35  percent  in  the  yield  of  rape  and  of 
43  percent  in  the  yield  of  clover ;  while  leucite  gave  an  increase  of  30 
percent  in  the  yield  of  rape  and  of  32  percent  in  the  yield  of  clover. 

In  1918  some  new  pots  with  fresh  peat  were  used  to  start  some 
new  series  for  the  production  of  other  crops.  The  average  results 
obtained  with  these  crops  during  1918  and  1919  are  recorded  in 
Table  8. 

TABLE  8. — EFFECT  OF  VARIOUS  FORMS  OF  POTASSIUM  ON  THE  PRODUCTION 
OF  VARIOUS  CROPS,  1918  AND  1919 

Yields  recorded  as  grams  per  pot,  air-dry  weight 


1>/vf 

ItJ 

18 

iyiy 

No. 

Treatment 

Barley 

Rape 

Beets1 

Flax 

Alsike 
clover 

1 

Lime                

45 

180 

(540) 

43 

76 

2 

L   kainit  

95 

240 

(840) 

62 

95 

3 

L   alunite  

46 

187 

(660) 

48 

86 

4 

L,  leucite  

65 

223 

(800) 

54 

141 

fields  recorded  as  harvested,  not  air-dry. 

Again  the  indications  are  very  favorable  for  the  use  of  leucite. 
The  increases  produced  by  this  material  and  by  kainit,  as  expressed 
on  a  percentage  basis,  may  be  summarized  as  follows : 


250 


BULLETIN  No.  232 


[March, 


Percentage  Increases  in  Yields 


Barley 

Kainit Ill 

Leucite    .  44 


Eape 
33 
24 


Beets 
55 

48 


Flax 
44 
25 


Clover 
25 
86 


These  results,  so  favorable  to  the  use  of  leucite  as  a  source  of 
potassium  for  soil  improvement  on  peaty  soils,  were  presented  in 
March,  1919,  to  the  Chemical  Research  Club  of  the  University  of 
Illinois.  At  this  meeting  Professor  S.  W.  Parr  called  attention  to 
the  shale  deposit  in  Union  county,  Illinois,  and  suggested  in  view  of 
the  results  obtained  with  leucite,  that  the  potassium  in  the  shale  might 
also  be  directly  available  for  crop  growth.  Professor  Parr  kindly 
offered  to  furnish  some  of  the  shale  for  use  in  pot-culture  tests,  in  the 
hope  that  the  potassium  which  it  contained  would  be  at  least  as  avail- 
able as  that  in  leucite.  The  suggestion  was  gladly  received  and  some 
new  pots  were  provided  for  testing  out  the  finely-ground  shale  as  a 
source  of  potassium  for  crop  production.  The  amount  of  potassium 
added  in  the  form  of  the  shale  was  the  same  as  was  added  in  the  other 
potassium-bearing  materials,  1.34  grams  per  pot.  The  results  obtained 
from  the  use  of  the  shale  in  comparison  with  those  obtained  from  the 
other  materials  are  recorded  in  Table  9. 

TABLE  9. — EFFECT  OF  VAEIOUS  FORMS  OF  POTASSIUM  ON  THE  PRODUCTION 
OF  VARIOUS  CROPS,  1919 

Yields  recorded  as  grams  per  pot,  air-dry  weight 


Pot  No. 

Treatment 

Sweet 
clover 

Eape 

Corn 
fodder 

Buck- 
wheat 

1 

57 

86 

67 

38 

2 

55 

84 

66 

34 

3 

L,  kainit  

65 

106 

91 

62 

4 

L    kuiii  i  t  

63 

108 

94 

59 

5 

L    aluiiito  

55 

90 

73 

39 

6 

L,  alunite  

57 

92 

72 

38 

7 

L,  leucite  

60 

104 

99 

75 

8 

L   leucite       

60 

110 

106 

65 

9 

L,  leueite,  magnesium  ehlorid, 
sodium  chlorid   

58 

94 

79 

64 

10 

L,  leucite,  magnesium  chlorid, 
sodium  chlorid   

58 

93 

83 

67 

11 

L    ignited  alunite  

71 

97 

112 

94 

12 

L    ignited  alunite  

70 

99 

116 

98 

13 

L    shale     

157 

170 

160 

99 

14 

L.  shale  . 

144 

165 

169 

103 

These  results  were  unexpectedly  favorable  to  the  shale.  Its  applica- 
tion gave  a  larger  increase  in  yield  than  did  any  other  form  of 
potassium,  even  larger  than  kainit  or  the  potassium  sulfate  from  the 


1921] 


PART  III:    FINELY  GROUND  SHALE  FOR  SOIL  IMPROVEMENT 


251 


ignited  alunite.  The  shale  produced  an  increase  in  the  yield  of  sweet 
clover  of  168  percent ;  of  rape,  96  percent ;  of  corn  fodder,  146  per- 
cent; and  of  buckwheat,  180  percent.  The  differences  in  yields  are 
truly  remarkable.  The  effect  of  the  treatment  is  perhaps  more  clearly 
brought  out  in  the  accompanying  illustrations. 

Even  with  such  a  crop  as  corn,  which  is  not  well  adapted  to  green- 
house work,  the  effect  of  the  shale  was  astonishing,  as  may  be  seen  by 
a  study  of  the  data  in  Table  10. 

TABLE  10. — EFFECT  OF  KAINIT  AND  OF  SHALE  ON  THE  PRODUCTION  OF  CORN,  1919 
Yields  recorded  as  grams  per  pot,  air-dry  weight 


Pot  No. 

Treatment 

Corn  fodder 

1 

208 

2 

203 

3 

233 

4 

L    kainit                

225 

5 

404 

6 

L    shale          .        

406 

Here  the  shale  actually  produced  an  increase  in  the  yield  of  corn 
fodder  of  98  percent ;  the  corn  on  the  shale  pots  grew  so  large  that  it 
was  necessary  to  move  it  outside  of  the  greenhouse.  The  effect  of  the 
shale  on  the  production  of  corn  is  clearly  shown  in  Fig.  1  (page  228). 

As  is  well  known,  there  is  another  type  of  soil  in  Illinois,  gray  silt 
loam,  which  responds  readily  to  the  application  of  soluble  potassium 
salts,  altho  the  response  is  usually  attributed  to  the  effect  of  the  soluble 
salt  rather  than  to  the  effect  of  potassium  as  a  plant  food.  There  is 
some  indication  that  the  shale  may  serve  as  a  source  of  potassium  for 
such  soils.  Buckwheat  and  corn  were  grown  in  the  greenhouse  on  this 
type  of  soil  treated  with  kainit  and  shale.  The  results  are  recorded 
iii  Table  11. 


TABLE  11. — EFFECT  OF  KAINIT  AND  OF  SHALE  ON  THE  PRODUCTION  OF  WHEAT 
ON  GRAY  SILT  LOAM,  1920 

Yields  recorded  as  grams  per  pot,  air-dry  weight 


Buckwhea 

t 

Pot  No. 

Treatment 

Grain 

Straw 

Total 
crop 

fodder 

1 

Lime  

22.50 

59.30 

82 

143 

2 

Lime  

22.10 

60.90 

83 

146 

3 

L,  kainit  

26.90 

69.10 

96 

181 

4 

L,  kainit  

2470 

68.30 

93 

165 

5 

L,  shale   

31.00 

72  (JO 

103 

154 

6* 

L.  shale  . 

28.20 

71.80 

100 

158 

252 


BULLETIN  No.  232 


In  the  production  of  the  buckwheat  there  was  an  increase  of  32 
percent  in  the  yield  of  grain,  and  of  19  percent  in  the  straw,  from  the 
use  of  shale.  There  was  also  a  slightly  increased  yield  of  corn  fodder 
from  the  application  of  shale. 

The  buckwheat,  in  1920,  was  grown  on  one  of  the  original  peat  soil 
series.  Alunite  had  shown  very  little  effect ;  so  it  was  decided  to  use 
these  alunite  pots  as  checks  this  year  and  to  apply  fresh  shale  to  the 
original  check  pots,  Nos.  1  and  2,  in  order  to  eliminate  the  possible 
effect  of  fresh  peat  soil.  Pots  13  and  14,  receiving  the  shale,  had  been 
recently  filled  with  peat,  while  the  remainder  of  the  series  had  been 
filled  three  years  previously.  It  was  thought  that  this  difference  might 
have  had  some  influence  on  the  remarkable  effect  of  the  shale,  and  so 
it  was  checked  out  as  indicated.  The  shale  on  the  original  check  pots 
raised  the  yield  of  buckwheat  in  1920  slightly  higher  than  in  the 
original  shale  pots,  Nos.  13,  and  14.  The  complete  data  are  recorded 
in  Table  12,  from  which  it  is  clearly  seen  that  the  effect  above  noted 
was  due  to  the  shale  itself  and  not  to  the  freshness  of  the  peat  soil. 

TABLE  12. — EFFECT  OF  VARIOUS  FORMS  OF  POTASSIUM  ON  THE  PRODUCTION 

OF  BUCKWHEAT,  1920 
Yields  recorded  as  grams  per  pot,  air-dry  weight 


Pot  No. 

Treatment 

Individual 

Average 

1 

Lime   (original  check)    shale  this  year      

35 

2 

Lime   (original  check),  shale  this  year  

34 

34.5 

3 

L    kainit                                       

22 

4 

L    kainit              

19 

20.5 

5 

L    alunite          

12 

6 

L,  alunite        

10 

11.0 

7 

L   leucite     

28 

8 

L,  leucite  

25 

26.5 

9 

10 

11 

L,  leucite,  magnesium  chlorid,  sodium  chlorid  .... 
L,  leucite,  magnesium  chlorid,  sodium  chlorid.  .  .  . 

L    ignited  alunite  ..          

38 
28 

31 

34.0 

12 

L,  ignited  alunite  

21 

26.0 

13 

L    shale             

35 

14 

L,  shale   

32 

33.5 

CONCLUSIONS 

This  pot-culture  work  in  the  greenhouse  indicates  marked  benefit  to  crops, 
resulting  from  applications  of  shale.  The  results  are  so  striking  and  of  such 
possible  economic  development  as  to  warrant  more  extended  investigations, 
particularly  in  the  field;  and  they  are  of  sufficient  general  interest  to  make 
advisable  their  presentation  at  this  time.  It  is  quite  evident  that  the  potassium 
in  this  shale  can  be  directly  used  by  crops  in  pot  cultures  under  greenhouse 
conditions. 


